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340
Aristotle's take on matter
Matter underlies and persists through substantial changes. A substance is only destoryed by losing form. -
370
Plato's take on matter
Non-material abstract forms(water,earth,air,and fire) and not the material world of change we feel through sensation posses the hghest and most basic kind of reality. -
425
Leucippus's take on matter
Matter is composed of atoms sepertaed by empty space through which the atoms move. Atoms are indivisible and unchangable -
430
Atomic Theory according to Democritus and Leucippus
- Matter is composed of atoms separated by empty space through which the atoms move.
- Atoms are solid, homogeneous, indivisible, and unchangeable.
- All apparent changes in matter result from changes in the groupings of atoms.
- There are different kinds of atoms that differ in size and shape.
- The properties of matter reflect the properties of the atoms the matter contains.
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432
Empedocles take on matter
Matter is the only principle of all things. Everything is made up of various ratios of earth,water,fire,and air. -
440
Democritus's take on matter
Matter consists of tiny indivisble, unchangeable particles called atoms. -
Law of Conservation by Antoine Laurent Lavoisier
Mass can never be created or destroyed -
Untied States Library of Congress
United States Library of Congress founded -
Daltons Atomic Theory
- all elements are composed of tiny indivisible particles called atoms. 2.Atoms of the same element are identicle. 3.Atoms of different elements can physically mix together or can chemically combine to form compunds 4.Chemical reactions occur when atoms are sepertated, joined, or rearranged. Atoms of one element are never changed into another element after a cheimical reation.
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Daltons Oxygen atom
http://www.youtube.com/watch?feature=player_embedded&v=3dWdMqZ2UOU
This video shows the oxygen atom. -
Louisiana Purchase
Senate ratifies the Louisiana Purchase Treaty, doubling the size of the United States -
Law of Compostions by John Dalton
In saomples of any chemical compund, the masses of the elements are always in the same proportion -
Law of Multiple Proportions by John Dalton
Whenever two elements form more than one compund, the different masses of oneelement that combine with the same mass of the other element are in the ratio of small whole numbers -
Schrodinger
Is a architect of Quantum Mechanics and Created the book "What is Life?" This created a huge progress in biology. -
J.J Thompson's discovery of the electron
Thompson discovered the the elctron while prefomring experiments on the nature of electric discharge in a high-vaccum, cathrod-ray tube. The unkown glwoing steam, he noticed, would bend toward a postiviley charged electron plate. This showed the particles we nevitivley charged. -
Thomson's Oxygen Atom
"On April 30, 1897, Joseph John Thomson announced that cathode rays were negatively charged particles which he called 'corpuscles.' He also announced that they had a mass about 1000 times smaller than a hydrogen atom, and he claimed that these corpuscles were the things from which atoms were built up."(Thomson Model) -
Raisn bread theory by JJ Thomson
After Eugen Goldstines discovery that atoms had postitive charges thomas decied the structure of atom is like raisin bread. THe basic body of atom is spherical object containing N electrons confined in homogeneous nutural jelly -
Thomson's Credit to the Discovery of the Electron
Thomson was given credit for the discovery of the electron even though we was not the first. -
Queen Victorias Death
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San Fransico Earthquake
San Francisco earthquake (est. magnitude 7.8) destroys much of city, killing at least 3,000; with 225,000-300,000 left homeless, $350 million in damages -
Ernest Rutherford's Alpha particles
Rutherford fired alpha particles at gold foil and foudn that most of the particles passed right through the foil, and some passed through at an angle. Some of the particles bounced back like a tennis ball hitting a wall. This exeriment showed matter has holes in it. -
Millikans oil drop experiment
The oild drop experiment determined the size of the charge on an electron and charge is quantized. In the experiment he balanced the donwward gravotational force and the upward eletrical and buoyant forces of charged oil droplets suspended between two metal plates. He calculated the charge of an electron to be 1.5924(17)×10−19 C -
Bhor's Model of an atom
In Bhor's model of an atom protons and nuetrons occupy a dense centeral region called the nucleus. Electrons orbit around the nucles much like the planets in the solar system. -
Quantum Mechanic Model
The theory of quantum mechanics explains the behavior of particles in the atomic and subatomic realms.
This model shows all of the different levels -
Louis De Broglie
de Broglie suggested that particles could sometimes behave as waves and waves could sometimes bahave as particles - the wave/particle duality of nature. He suggested a simple equation that would relate the two: Particles have momentum (p), waves have wavelengths (l) and the two are related by the equation"(Modern Atomic Theory.) Same equation as Plancks quantum theory. -
Heisenberg's Uncertainty Principle
The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.
--Heisenberg, uncertainty paper, 1927
Nothing is known for sure in the atomic theory. -
Dustbowl
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Chadwicks Discovery of the Nuetron
In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons - elementary particles devoid of any electrical charge -
Rutherford's Oxygen Atom Model
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Planck's Quantum Theory
"(i) The radiant energy which is emitted or absorbed by the black body is not continuous but discontinuous in the form of small discrete packets of energy, each such packet of energy is called a 'quantum'. In case of light, the quantum of energy is called a 'photon'. (ii) The energy of each quantum is directly proportional to the frequency (v) of the radiation, i.e. E ∞ V or E hv = hc/λ Where, λ Planck's constant = 6.62×10–27 erg. sec. or 6.62×10-24 joulessec"(Study Material, Chemistry, )
